This collapse could spell trouble for life on Earth, since the magnetic field stabilizes ozone molecules, shielding the planet from ultraviolet radiation. Singer points out that recent work suggests modern humans adapted to have protective genes after Neanderthals suffered from radiation during an excursion that deteriorated the magnetic field. But now we know those timings much better. If this weakening and the recent migration of the northern magnetic pole are indicative of a looming field reversal, it could have serious implications for technologies that rely on satellites, which may be damaged by cosmic radiation.
However, Singer cautions that a reversal not likely to happen for the next couple millennia. That should buy humanity some time to better shield its technologies from radiation by the next reversal.
The rotation and convection of molten iron at the center of the planet creates a dynamo effect, generating Earth's magnetic field. Schematic illustration of the invisible magnetic field lines generated by the Earth, represented as a dipole magnet field.
In actuality, our magnetic shield is squeezed in closer to Earth on the Sun-facing side and extremely elongated on the night-side due to the solar wind. And if any objects were heated and cooled several times, several magnetic patterns will be superimposed.
Lastly, their reliability is dependent on the objects remaining in the same location that the heating took place. Despite these difficulties, researchers have largely mapped modern changes in the magnetic field beneath western Europe and the Middle East. Juvenile loggerhead turtles dig their way out of underground nests on the beaches of Florida, enter the sea and travel far into the Atlantic Ocean sometimes completely traversing it. Then, after many years, they return to the same Florida beaches on which they were born.
They navigate this featureless, 9,mile 14,km journey by detecting the strength and direction of the magnetic field. Additionally, Earth is constantly bombarded with a stream of charged particles arriving from the Sun and cosmic rays, mostly protons and atomic nuclei, from deep space.
In the period leading up to a reversal, the magnetic field becomes weaker and significantly less effective at shielding us from those particles. While some geologists note that mass extinctions seem to correlate with these time periods, humans or our ancestors have been on Earth for several million years. During that time there have been many reversals, and there is no obvious correlation with human development.
The direct effect on mankind could be only slight, but not so for technology. We use artificial satellites for navigation, television broadcasting, weather forecasting, environmental monitoring and communication of all kinds. Without the protection of a magnetic field, these satellites could be seriously disrupted by solar wind or cosmic rays colliding with electronic circuits. Recent geological studies have suggested a possible reason for the anomaly. It is widely believed that our Moon was formed when Earth was struck by the planet Theia 4.
It now appears that the remains of Theia may lie beneath our feet. Scientists suggest that these rock masses are the missing remains of Theia and that they interfere with the convection of molten iron — giving rise to the weak magnetic field in the South Atlantic. Regardless, the seriousness of a magnetic reversal will depend on how long the reversal takes to complete. If it slowly shifts for many thousands of years , it is possible that migratory creatures, and mankind as well, will be able to adapt.
In the meantime, we have much to learn about what is happening deep within our planet. Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. View our Privacy Policy. By signing up you may also receive reader surveys and occasional special offers. We do not sell, rent or trade our email lists. Login or Register Customer Service. Discover World-Changing Science. Get smart. Sign up for our email newsletter. Sign Up.
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